{"@type": "dcat:Dataset", "accessLevel": "public", "bureauCode": ["026:00"], "contactPoint": {"@type": "vcard:Contact", "fn": "MAST Archive", "hasEmail": "mailto:archive@stsci.edu"}, "description": "The Guide Star Catalog II (GSC-II) is an all-sky optical catalog based on 1\" resolution scans of the photographic Sky Survey plates, at two epochs and three bandpasses, from the Palomar and UK Schmidt telescopes. This all-sky catalog will ultimately contains positions, proper motions, classifications, and magnitudes in multiple bandpasses for almost a billion objects down to approximately Jpg=21, Fpg=20. The GSC-II is currently used for HST Bright Object Protection and HST pointing. Looking ahead, the GSC-II will form the basis of the Guide Star Catalog for JWST. This was constructed in collaboration with ground-based observatories for use with the GEMINI, VLT and GALILEO telescopes", "distribution": [{"@type": "dcat:Distribution", "downloadURL": "http://gsss.stsci.edu/Catalogs/GSC/GSC2/GSC2.htm", "format": "BIN", "mediaType": "application/octet-stream"}, {"@type": "dcat:Distribution", "downloadURL": "http://gsss.stsci.edu/webservices/vo/ConeSearch.aspx?CAT=GSC23&", "format": "BIN", "mediaType": "application/octet-stream"}], "identifier": "ivo://archive.stsci.edu/gsc/gsc2.3", "keyword": ["__"], "landingPage": "ivo://archive.stsci.edu/gsc/gsc2.3", "license": "https://www.usa.gov/government-works", "modified": "2026-06-22", "programCode": ["026:000"], "publisher": {"@type": "org:Organization", "name": "MAST:  Mikulski Archive at Space Telescope"}, "theme": ["Astrophysics"], "title": "Guide Star Catalog 2.3 Cone Search"}